Layout--iOS

时间:2024-01-01 14:16:51

// 系统的约束代码

@implementation ViewController

- (void)viewDidLoad {

    [super viewDidLoad];

    UIView *superView = self.view;

    UIView *viewDemo = [[UIView alloc] init];

    viewDemo.translatesAutoresizingMaskIntoConstraints = NO;

    viewDemo.backgroundColor = [UIColor orangeColor];

    [superView addSubview:viewDemo];

    UIEdgeInsets padding = UIEdgeInsetsMake(, , , );

    [superView addConstraints:@[

           // viewDemo顶部距离父视图superView顶部距离为padding.top(即为:10),

                               [NSLayoutConstraint constraintWithItem:viewDemo attribute:NSLayoutAttributeTop relatedBy:NSLayoutRelationEqual toItem:superView attribute:NSLayoutAttributeTop multiplier: constant:padding.top],

                               [NSLayoutConstraint constraintWithItem:viewDemo attribute:NSLayoutAttributeLeft relatedBy:NSLayoutRelationEqual toItem:superView attribute:NSLayoutAttributeLeft multiplier: constant:padding.left],

                               [NSLayoutConstraint constraintWithItem:viewDemo attribute:NSLayoutAttributeRight relatedBy:NSLayoutRelationEqual toItem:superView attribute:NSLayoutAttributeRight multiplier: constant:-padding.right],

                               [NSLayoutConstraint constraintWithItem:viewDemo attribute:NSLayoutAttributeBottom relatedBy:NSLayoutRelationEqual toItem:superView attribute:NSLayoutAttributeBottom multiplier: constant:-padding.bottom]

                               ]];

}

// 注:若是把右边约束去掉,改为如下语句

// [NSLayoutConstraint constraintWithItem:viewDemo attribute:NSLayoutAttributeWidth relatedBy:NSLayoutRelationEqual toItem:superView attribute:NSLayoutAttributeWidth multiplier:0.5 constant:0]

// 则viewDemo的宽度变为superView的0.5倍!!

//***************************************************

// VFL语言

  UIView *viewLeft = [[UIView alloc] init];

    viewLeft.translatesAutoresizingMaskIntoConstraints = NO;

    viewLeft.backgroundColor = [UIColor orangeColor];

    [self.view addSubview:viewLeft];

    UIView *viewRight = [[UIView alloc] init];

    viewRight.translatesAutoresizingMaskIntoConstraints = NO;

    viewRight.backgroundColor = [UIColor redColor];

    [self.view addSubview:viewRight];

    // horizontal:水平方向距左边10,距右边10

    //简单说来,NSDictionaryOfVariableBindings(scrollView)就等于@{@”scrollView”: scrollView}

    NSDictionary *constraintDict = NSDictionaryOfVariableBindings(viewLeft,viewRight);

    NSArray *hConstraintArrayLeft = [NSLayoutConstraint constraintsWithVisualFormat:@"H:|-(10)-[viewLeft]-(10)-|" options: metrics:nil views:constraintDict];

    // vertical: 垂直方向距顶部30,控件高度100

    NSArray *vConstraintArrayLeft = [NSLayoutConstraint constraintsWithVisualFormat:@"V:|-(30)-[viewLeft(100)]" options: metrics:nil views:constraintDict];

    // 添加到父视图上

    [self.view addConstraints:hConstraintArrayLeft];

    [self.view addConstraints:vConstraintArrayLeft];

    NSArray *hConstraintArrayRight = [NSLayoutConstraint constraintsWithVisualFormat:@"H:|-(10)-[viewRight]-(10)-|" options: metrics:nil views:constraintDict];

    // viewRight距viewLeft的垂直距离为50

    NSArray *vConstraintArrayRight = [NSLayoutConstraint constraintsWithVisualFormat:@"V:[viewLeft]-(50)-[viewRight(200)]" options: metrics:nil views:constraintDict];

    [self.view addConstraints:hConstraintArrayRight];

    [self.view addConstraints:vConstraintArrayRight];

//***************************************************

// 三方库:Masonry

// 居中

// 快速定义一个weakSelf,用于block里面,防止循环引用

#define WS(weakSelf)  __weak __typeof(&*self)weakSelf = self

WS(ws);

UIView *sv = [UIView new];

sv.backgroundColor = [UIColor orangeColor];

// 在做autoLayout之前 一定要先将view添加到superView上 否则会报错

[self.view addSubview:sv];

[sv mas_makeConstraints:^(MASConstraintMaker *make) {

// 居中

make.center.equalTo(ws.view);

// 设置size

make.size.mas_equalTo(CGSizeMake(300, 300));

}];

3. [初级] 让两个高度为150的view垂直居中且等宽且等间隔排列 间隔为10(自动计算其宽度)

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int padding1 = 10;
[sv2 mas_makeConstraints:^(MASConstraintMaker *make) {
    make.centerY.mas_equalTo(sv.mas_centerY);
    make.left.equalTo(sv.mas_left).with.offset(padding1);
    make.right.equalTo(sv3.mas_left).with.offset(-padding1);
    make.height.mas_equalTo(@150);
    make.width.equalTo(sv3);
}];
[sv3 mas_makeConstraints:^(MASConstraintMaker *make) {
    make.centerY.mas_equalTo(sv.mas_centerY);
    make.left.equalTo(sv2.mas_right).with.offset(padding1);
    make.right.equalTo(sv.mas_right).with.offset(-padding1);
    make.height.mas_equalTo(@150);
    make.width.equalTo(sv2);
}];

代码效果

Layout--iOS

这里我们在两个子view之间互相设置的约束 可以看到他们的宽度在约束下自动的被计算出来了

4. [中级] 在UIScrollView顺序排列一些view并自动计算contentSize

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UIScrollView *scrollView = [UIScrollView new];
scrollView.backgroundColor = [UIColor whiteColor];
[sv addSubview:scrollView];
[scrollView mas_makeConstraints:^(MASConstraintMaker *make) {
    make.edges.equalTo(sv).with.insets(UIEdgeInsetsMake(5,5,5,5));
}];
UIView *container = [UIView new];
[scrollView addSubview:container];
[container mas_makeConstraints:^(MASConstraintMaker *make) {
    make.edges.equalTo(scrollView);
    make.width.equalTo(scrollView);
}];
int count = 10;
UIView *lastView = nil;
for ( int i = 1 ; i <= count ; ++i )
{
    UIView *subv = [UIView new];
    [container addSubview:subv];
    subv.backgroundColor = [UIColor colorWithHue:( arc4random() % 256 / 256.0 )
                                      saturation:( arc4random() % 128 / 256.0 ) + 0.5
                                      brightness:( arc4random() % 128 / 256.0 ) + 0.5
                                           alpha:1];
     
    [subv mas_makeConstraints:^(MASConstraintMaker *make) {
        make.left.and.right.equalTo(container);
        make.height.mas_equalTo(@(20*i));
         
        if ( lastView )
        {
            make.top.mas_equalTo(lastView.mas_bottom);
        }
        else
        {
            make.top.mas_equalTo(container.mas_top);
        }
    }];
     
    lastView = subv;
}
[container mas_makeConstraints:^(MASConstraintMaker *make) {
    make.bottom.equalTo(lastView.mas_bottom);
}];

头部效果

Layout--iOS

尾部效果

Layout--iOS

从scrollView的scrollIndicator可以看出 scrollView的内部已如我们所想排列好了

这里的关键就在于container这个view起到了一个中间层的作用 能够自动的计算uiscrollView的contentSize

5. [高级] 横向或者纵向等间隙的排列一组view

很遗憾 autoLayout并没有直接提供等间隙排列的方法(Masonry的官方demo中也没有对应的案例) 但是参考案例3 我们可以通过一个小技巧来实现这个目的 为此我写了一个Category

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@implementation UIView(Masonry_LJC)
- (void) distributeSpacingHorizontallyWith:(NSArray*)views
{
    NSMutableArray *spaces = [NSMutableArray arrayWithCapacity:views.count+1];
     
    for ( int i = 0 ; i < views.count+1 ; ++i )
    {
        UIView *v = [UIView new];
        [spaces addObject:v];
        [self addSubview:v];
         
        [v mas_makeConstraints:^(MASConstraintMaker *make) {
            make.width.equalTo(v.mas_height);
        }];
    }    
     
    UIView *v0 = spaces[0];
     
    __weak __typeof(&*self)ws = self;
     
    [v0 mas_makeConstraints:^(MASConstraintMaker *make) {
        make.left.equalTo(ws.mas_left);
        make.centerY.equalTo(((UIView*)views[0]).mas_centerY);
    }];
     
    UIView *lastSpace = v0;
    for ( int i = 0 ; i < views.count; ++i )
    {
        UIView *obj = views[i];
        UIView *space = spaces[i+1];
         
        [obj mas_makeConstraints:^(MASConstraintMaker *make) {
            make.left.equalTo(lastSpace.mas_right);
        }];
         
        [space mas_makeConstraints:^(MASConstraintMaker *make) {
            make.left.equalTo(obj.mas_right);
            make.centerY.equalTo(obj.mas_centerY);
            make.width.equalTo(v0);
        }];
         
        lastSpace = space;
    }
     
    [lastSpace mas_makeConstraints:^(MASConstraintMaker *make) {
        make.right.equalTo(ws.mas_right);
    }];
     
}
- (void) distributeSpacingVerticallyWith:(NSArray*)views
{
    NSMutableArray *spaces = [NSMutableArray arrayWithCapacity:views.count+1];
     
    for ( int i = 0 ; i < views.count+1 ; ++i )
    {
        UIView *v = [UIView new];
        [spaces addObject:v];
        [self addSubview:v];
         
        [v mas_makeConstraints:^(MASConstraintMaker *make) {
            make.width.equalTo(v.mas_height);
        }];
    }
     
     
    UIView *v0 = spaces[0];
     
    __weak __typeof(&*self)ws = self;
     
    [v0 mas_makeConstraints:^(MASConstraintMaker *make) {
        make.top.equalTo(ws.mas_top);
        make.centerX.equalTo(((UIView*)views[0]).mas_centerX);
    }];
     
    UIView *lastSpace = v0;
    for ( int i = 0 ; i < views.count; ++i )
    {
        UIView *obj = views[i];
        UIView *space = spaces[i+1];
         
        [obj mas_makeConstraints:^(MASConstraintMaker *make) {
            make.top.equalTo(lastSpace.mas_bottom);
        }];
         
        [space mas_makeConstraints:^(MASConstraintMaker *make) {
            make.top.equalTo(obj.mas_bottom);
            make.centerX.equalTo(obj.mas_centerX);
            make.height.equalTo(v0);
        }];
         
        lastSpace = space;
    }
     
    [lastSpace mas_makeConstraints:^(MASConstraintMaker *make) {
        make.bottom.equalTo(ws.mas_bottom);
    }];
}
@end

简单的来测试一下

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UIView *sv11 = [UIView new];
UIView *sv12 = [UIView new];
UIView *sv13 = [UIView new];
UIView *sv21 = [UIView new];
UIView *sv31 = [UIView new];
sv11.backgroundColor = [UIColor redColor];
sv12.backgroundColor = [UIColor redColor];
sv13.backgroundColor = [UIColor redColor];
sv21.backgroundColor = [UIColor redColor];
sv31.backgroundColor = [UIColor redColor];
[sv addSubview:sv11];
[sv addSubview:sv12];
[sv addSubview:sv13];
[sv addSubview:sv21];
[sv addSubview:sv31];
//给予不同的大小 测试效果
[sv11 mas_makeConstraints:^(MASConstraintMaker *make) {
    make.centerY.equalTo(@[sv12,sv13]);
    make.centerX.equalTo(@[sv21,sv31]);
    make.size.mas_equalTo(CGSizeMake(40, 40));
}];
[sv12 mas_makeConstraints:^(MASConstraintMaker *make) {
    make.size.mas_equalTo(CGSizeMake(70, 20));
}];
[sv13 mas_makeConstraints:^(MASConstraintMaker *make) {
    make.size.mas_equalTo(CGSizeMake(50, 50));
}];
[sv21 mas_makeConstraints:^(MASConstraintMaker *make) {
    make.size.mas_equalTo(CGSizeMake(50, 20));
}];
[sv31 mas_makeConstraints:^(MASConstraintMaker *make) {
    make.size.mas_equalTo(CGSizeMake(40, 60));
}];
[sv distributeSpacingHorizontallyWith:@[sv11,sv12,sv13]];
[sv distributeSpacingVerticallyWith:@[sv11,sv21,sv31]];
[sv showPlaceHolderWithAllSubviews];
[sv hidePlaceHolder];

代码效果

Layout--iOS

perfect! 简洁明了的达到了我们所要的效果

这里所用的技巧就是 使用空白的占位view来填充我们目标view的旁边 这点通过图上的空白标注可以看出来

引自:http://www.cocoachina.com/ios/20141219/10702.html

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